Sir Erasmus Ommanney was born on May 22, 1814, in London, England.

He was a Royal Navy officer and an Arctic explorer. Born into a family of distinguished Royal Navy admirals, he entered the Royal Navy in 1826 at the age of twelve. He participated in the Battle of Navarino in 1827. In 1833, he passed his naval examination and was promoted lieutenant in 1835. In 1838, he went on an Arctic expedition in search of missing whalers. Three years later, on another Arctic expedition, he served as Captain of H.M.S. Assistance and found the remains of Sir John Franklin's expedition at Cape Riley, Devon Island. In 1853, Ommanney was elected a Fellow of the Royal Astronomical Society. During the Crimean War of 1854-1856, he commanded the naval force in the White Sea and the Gulf of Riga. In 1859, he was transferred to the Mediterranean Fleet. In 1868, he was elected Fellow of the Royal Society. In 1871, he was promoted to vice admiral and retired in 1875. He became an Admiral in 1877. He was also a Fellow of the Royal Geographical Society and a member of the British Association for the Advancement of Science. He served as a Justice of the Peace for Hampshire and a member of the Thames conservancy.

In 1849, he married Emily Mary Smith (1818–1857), and in 1862, he married Mary Stone (1825–1906). He died on December 21, 1904, in Southsea, Portsmouth, Portsea Island, England.